This invention relates to molded articles for photographic photosensitive materials.
As the molded articles for photographic photosensitive materials, there are packaging films for photographic photosensitive materials, containers for a photographic film cartridge and the like.
A conventional packaging film for photographic photosensitive materials is disclosed in Japanese Patent KOKOKU No. 63-26697, and is composed of a polyester layer, an adhesive layer, an aluminum foil and a polyolefin resin layer containing light-shielding material and nonionic antistatic agent laminated in this order from the outside. Another conventional packaging film for photosensitive materials is disclosed in Japanese Patent KOKOKU No. 2-2700, and contains at least one light-shielding film layer comprising a polymer belonging to polyethylene and more than 1 wt. % of light-shielding material, and more than 50 wt. % of the total polymers belonging to polyethylene is L-LDPE resin. The packaging film is excellent in physical strength and heat sealing properties.
A conventional container body for a photographic film cartridge is disclosed in Japanese Patent KOKAI No. 61-73947, and is formed of a resin composition of polypropylene resin containing 0.05 to 1 wt. % of fatty acid amide lubricant. The container body has various advantages, such as sharp shortening of injection molding cycle, sharp decrease of molding troubles, excellent in slipping character between the container bodies resulting in rare occurrence of abrasion, etc. Another conventional container body for a photographic film cartridge is disclosed in Japanese Utility Model KOKOKU No. 2-33236, and is formed of a polypropylene resin having specific properties containing 0.1 to 3 wt. % of light-shielding material. The container body has also various advantages, such as shortening of injection molding cycle, sharp decrease of molding troubles, great improvement in dropping strength, etc.
However, the above conventional packaging films and cotainer bodies have various problems caused by the migration of antistatic agent or lubricant to the surface of the molded article due to the use of crystalline resin. Moreover, in the case of the container bodies requiring transparency, organic nucleating agent is blended in order to improve the transparency (Japanese Patent KOKOKU No. 4-58616), and they have various problems caused by the migration to the surface or thermal decomposition of the organic nucleating agent. That is, the above packaging films are inferior in the permanence of antistatic properties, and antistatic agent gradually bleed out to induce greasiness, blocking, defective heat seal and the like. When the blending amount of light-shielding material is much, various problems occur, such as adverse affect upon photographic properties, increase of lump generation, defective light-shielding by pinholes generated by the shaking during conveying, and the like.
In the conventional transparent container bodies, fatty acid amide lubricant gradually bleed out of the surface resulting in the decrease of transparency, in the generation of white powder or the like. Organic nucleating agent, antistatic agent and lubricant tend to be oxidized and to decompose with heat in molten resin at a high temperature, and adversely affect photographic photosensitive materials, such as fogging or sensitivity deviation. Lumps and coloring troubles also occur to degrade appearance of molded articles. When the blending amount of light-shielding material is much, various problems occur, such as generation of lumps due to insufficient dispersion of light-shielding material, decrease of dropping strength, degradation of photographic properties, such as fogging and sensitivity deviation. These are particularly problems as the container body for a high sensitivity photographic negative film not less than ISO photographic speed 100.